According to the Poly Language Page at polyamorysociety.org,
Polyamory n : is the nonpossessive, honest, responsible and ethical philosophy and practice of loving multiple people simultaneously. Polyamory emphasizes consciously choosing how many partners one wishes to be involved with, rather than accepting social norms which dictate loving only one person at a time. Polyamory is an umbrella term which integrates traditional multi-partner relationship terms with more evolved egalitarian terms. Polyamory embraces sexual equality and all sexual orientations towards an expanded circle of spousal intimacy and love. Polyamory is from the root words poly, meaning many, and amor, meaning love, hence, many loves, or polyamory.
Comparing your description to the definition, it sounds like polyamory to me.